Time evolution of the separation, d, between the centers of interacting galaxies for five cases. Sim. No. 1 and 15 are central collisions (α_b = 0°) at different initial inclinations (see Table 2). For Sim. No. 3 (α_b = 20°), different interaction stages are visualized in Fig. 1. Sim. No. 6 and 18 are examples for grazing interactions at α_b = 45°. The dashed gray line marks a separation of 10 kpc, corresponding to the diameter of the center regions of the initial disks.